Administrator terminal, participant terminal, right holder terminal, user terminal, content utulization system, administratior program, participant program, right holder program, user program, and data structure of state data

ABSTRACT

Pieces of information on multiple file management systems are managed by one contract in a distributed ledger. An administrator terminal ( 1 ) includes: a file management system generation unit ( 122 ) that issues a contract generation transaction for generating, in blockchain data (B), a contract in which a network identifier that identifies a file management system ( 9 ) is associated with an identifier of a participant terminal ( 10 ) in a blockchain system ( 6 ), and notifying the participant terminal ( 10 ) of the network identifier and an identifier of the contract; and a file management control unit ( 123 ) that issues a registration transaction for registering, in the contract, connection information of the administrator terminal ( 1 ) in the file management system ( 9 ), acquires connection information of the participant terminal ( 10 ) in the file management system ( 9 ) from the contract, and establishes a P2P connection with the participant terminal ( 10 ) based on the acquired connection information.

TECHNICAL FIELD

The present invention relates to an administrator terminal, aparticipant terminal, a right holder terminal, and a user terminal foruse in a content use system that includes a file management systemmanaged by an administrator and a distributed ledger system having adistributed ledger, and also relates to the content use system, anadministrator program, a participant program, a right holder program, auser program, and a data structure of state data.

BACKGROUND ART

Blockchain which is one type of a decentralized distributed ledger isused for transactions of digital cryptocurrencies. In the blockchain,pieces of information on transactions of cryptocurrencies communicatedamong participants are collected in units of blocks to form theblockchain. Regarding a structure of the blockchain, as the term chainimplies, the blockchain is recorded in such a way that each block islinked to an immediately preceding block. Specifically, each block islinked one another by including a hash value of the immediatelypreceding block in each block.

Accordingly, if transaction information included in a block at a certainpoint in time is to be falsified, it is necessary to falsify all blocksat and after the falsified block because a hash value of the falsifiedblock changes. When a block is to be added, it is necessary to perform avery computationally intensive process (mining) to find additionalinformation (a nonce) such that the hash value of the added block meetscertain conditions, and therefore, the blockchain is formed using amechanism that is very robust against the falsification.

Also, a programmable blockchain has been proposed in Ethereum. Programcode which is also called a contract is registered in the blockchain inadvance. If a transaction that designates contract execution is input,the program code is executed if the transaction is included in a block.The execution result is stored in state data of the blockchain.

IPFS (InterPlanetary File System) is an example of a distributed filemanagement system (file management system) that does not presumeprivileged nodes (see Non Patent Literature 1). In IPFS, a file isdivided into chunks of a certain size and managed by terminals thatbelong to the IPFS. A file is recognized by an identifier generated froma hash value, and the falsification of the file is not possible. IPFScan ensure the transparency and reliability by its dispersibility and anID structure.

Also, in view of the fact that the blockchain has a mechanism that isvery robust against the falsifications of the blockchain, there is asystem that integrates a file management system and a blockchain (seeNon Patent Literature 2). In Non Patent Literature 2, a file is dividedinto chunks. Each chunk is organized in a DAG (Directed Acyclic Graph),and each chunk contains information on a chunk of a link destination. InNon Patent Literature 2, identifiers of all of the chunks that form DAGare individually registered in the blockchain.

CITATION LIST Non Patent Literature

-   [Non Patent Literature 1] Juan Banet, “IPFS-Content Addressed,    Versioned, P2P File System (DRAFT 3)”, [Online], [Retrieved on Oct.    30, 2018], Internet    <URL:https://ipfs.io/ipfs/QmR7GSQM93Cx5eAg6a6yRzNdelFQv7uL6X10    4k7zrJa3LX/ipfs.draft3.pdf>.-   [Non Patent Literature 2] Mathis Steichen, et al.,    “Blockchain-Based, Decentralized Access Control for IPFS”, [Online],    [Retrieved on Oct. 15, 2018], Internet    <URL:https://www.researchgate.net/publication/327034734 Blockc    hain-Based Decentralized Access Control for IPFS>.

SUMMARY OF THE INVENTION Technical Problem

In Non Patent Literature 2, one file management system corresponds toone contract of the blockchain, and files of the file management systemare managed by one contract of the blockchain. However, in general, inorder to prevent the sharing of a file with a third party, the filemanagement system is often operated separately for each operatingprocess.

In Non Patent Literature 2, if an attempt is made to link one contractwith multiple file management systems, pieces of information on multipleoperating processes will be mixed in one contract. As a result, it maynot be possible to ensure the confidentiality between the operatingprocesses. Also, the leakage of an address of an administrator of thecontract may affect each file management system and operating process.

In view of this, the expectation is made for the development of amechanism according to which information of multiple file managementsystems can be managed by a single contract that corresponds to the filemanagement systems in the distributed ledger.

Accordingly, an object of the present invention is to provide anadministrator terminal, a participant terminal, a right holder terminal,a user terminal, a content use system, an administrator program, aparticipant program, a right holder program, a user program, and a datastructure of state data that enable information of a plurality of filemanagement systems to be managed by a single contract that correspondsto the file management systems in a distributed ledger.

Means for Solving the Problem

In order to solve the above problems, a first feature of the presentinvention relates to an administrator terminal used for a content usesystem that includes a file management system managed by anadministrator, a distributed ledger system including a distributedledger, the administrator terminal used by the administrator, and aparticipant terminal used by a participant who participates in the filemanagement system. The administrator terminal according to the firstfeature of the present invention includes a file management systemgeneration unit that issues a contract generation transaction forgenerating, in the distributed ledger, a contract in which a networkidentifier that identifies the file management system is associated withan identifier of the participant terminal in the distributed ledgersystem, and notifying the participant terminal of the network identifierand an identifier of the contract, and a file management control unitthat issues a registration transaction for registering, in the contract,connection information of the administrator terminal in the filemanagement system, acquires connection information of the participantterminal in the file management system from the contract, andestablishes a P2P connection with the participant terminal based on theacquired connection information.

A second feature of the present invention relates to a participantterminal used for a content use system that includes a file managementsystem managed by an administrator, a distributed ledger systemincluding a distributed ledger, an administrator terminal used by theadministrator, and the participant terminal used by a participant whoparticipates in the file management system. The participant terminalaccording to the second feature of the present invention includes a filemanagement control unit that, in response to being notified by thedistributed ledger system of an identifier of a contract thatcorresponds to a network identifier that identifies the file managementsystem, issues a registration transaction for registering, in thecontract that corresponds to the notified contract identifier,connection information of the participant terminal in the filemanagement system, acquires connection information of the administratorterminal from the contract that corresponds to the notified contractidentifier, and establishes a P2P connection with the administratorterminal based on the acquired connection information.

A third feature of the present invention relates to a right holderterminal used for a content use system that includes a file managementsystem, a distributed ledger system having a distributed ledger, and theright holder terminal used by a right holder of a content piece. Theright holder terminal according to the third feature of the presentinvention includes a storage device for storing file management controldata in which a network identifier that identifies the file managementsystem is associated with an identifier of a contract that is held inthe distributed ledger system and corresponds to the network identifier,a registration unit that issues a right holder registration transactionfor registering the network identifier of the file management system inwhich a content piece is to be registered, an identifier of the contentpiece in the file management system, and connection information of theright holder terminal in the file management system, in the contractthat corresponds to the network identifier, and a file managementcontrol unit that gives a notification that the right holder terminalhas the content piece via the file management system.

A fourth feature of the present invention relates to a user terminalused for in a content use system that includes a file management system,a distributed ledger system having a distributed ledger, a right holderterminal used by a right holder of a content piece, and the userterminal used by a user of the content piece. The user terminalaccording to the fourth feature of the present invention includes astorage device that stores file management control data in which anetwork identifier that identifies the file management system isassociated with an identifier of a contract that is held in thedistributed ledger system and corresponds to the network identifier, anda file management control unit that holds routing data that is to beheld by the user terminal in response to being notified that the rightholder terminal has the content piece via the file management system.

A fifth feature of the present invention relates to a right holderterminal used for in a content use system that includes a filemanagement system, a distributed ledger system including a distributedledger, the right holder terminal used by a right holder of a contentpiece, and a user terminal used by a user of the content piece. Theright holder terminal according to the fifth feature of the presentinvention includes a storage device that stores file management controldata in which a network identifier that identifies the file managementsystem is associated with an identifier of a contract that is held inthe distributed ledger system and corresponds to the network identifier,a user registration unit that issues a user setting transaction forassociating, in the contract that corresponds to the network identifierof the file management system that manages the content piece, anidentifier of the content piece with connection information of the userterminal that is to use the content piece in the file management system,and a file management control unit that, in response to receiving anacquisition request for acquisition of the content piece from the userterminal via the file management system, transmits the content piece tothe user terminal via the file management system if connectioninformation of the user terminal is associated with the identifier ofthe content piece in the contract.

A sixth feature of the present invention relates to a user terminal usedfor in a content use system that includes a file management system, adistributed ledger system including a distributed ledger, a right holderterminal used by a right holder of a content piece, and the userterminal used by a user of the content piece, and the user terminalincludes a storage device that stores file management control data inwhich a network identifier that identifies the file management system isassociated with an identifier of a contract that is held in thedistributed ledger system and corresponds to the network identifier, anda file management control unit that acquires connection information ofthe right holder terminal from the contract that corresponds to thenetwork identifier of the file management system that manages thecontent piece, and requests the content piece from the right holderterminal via the file management system.

A seventh feature of the present invention relates to a content usesystem that includes a file management system managed by anadministrator, a distributed ledger system including a distributedledger, an administrator terminal used by the administrator, and aparticipant terminal used by a participant who participates in the filemanagement system. In the content use system according to the seventhfeature of the present invention, the administrator terminal includes afile management system generation unit that issues a contract generationtransaction for generating, in the distributed ledger, a contract inwhich a network identifier that identifies the file management system isassociated with an identifier of the participant terminal in thedistributed ledger system, and notifying the participant terminal of thenetwork identifier and an identifier of the contract, and a filemanagement control unit that issues a registration transaction forregistering, in the contract, connection information of theadministrator terminal in the file management system, acquiresconnection information of the participant terminal in the filemanagement system from the contract, and establishes a P2P connectionwith the participant terminal based on the acquired connectioninformation, and the participant terminal includes a file managementcontrol unit that, in response to being notified by the distributedledger system of the identifier of the contract that corresponds to thenetwork identifier that identifies the file management system, issues aregistration transaction for registering, in the contract thatcorresponds to the notified contract identifier, connection informationof the participant terminal in the file management system, acquiresconnection information of the administrator terminal from the contractthat corresponds to the notified contract identifier, and establishes aP2P connection with the administrator terminal based on the acquiredconnection information.

An eighth feature of the present invention relates to a content usesystem that includes a file management system, a distributed ledgersystem including a distributed ledger, a right holder terminal used by aright holder of a content piece, and a user terminal used by a user ofthe content piece. In the content use system according to the eighthfeature of the present invention, the right holder terminal includes astorage device that stores file management control data in which anetwork identifier that identifies the file management system isassociated with an identifier of a contract that is held in thedistributed ledger system and corresponds to the network identifier, aregistration unit that issues a right holder registration transactionfor registering the network identifier of the file management system inwhich a content piece is to be registered, an identifier of the contentpiece in the file management system, and connection information of theright holder terminal in the file management system, in the contractthat corresponds to the network identifier, and a file managementcontrol unit that notifies that the right holder terminal has thecontent piece via the file management system, and the user terminalincludes a storage device that stores the file management control data,and a file management control unit that holds routing data that is to beheld by the user terminal in response to being notified that the rightholder terminal has the content piece via the file management system.

A ninth feature of the present invention relates to a content use systemthat includes a file management system, a distributed ledger systemincluding a distributed ledger, a right holder terminal used by a rightholder of a content piece, and a user terminal used by a user of thecontent piece. In the content use system according to the ninth featureof the present invention, the right holder terminal includes a storagedevice that stores file management control data in which a networkidentifier that identifies the file management system is associated withan identifier of a contract that is held in the distributed ledgersystem and corresponds to the network identifier, a user registrationunit that issues a user setting transaction for associating, in thecontract that corresponds to the network identifier of the filemanagement system that manages the content piece, an identifier of thecontent piece with connection information of the user terminal that isto use the content piece in the file management system, and a filemanagement control unit that, in response to receiving an acquisitionrequest for acquisition of the content piece via the file managementsystem from the user terminal, transmits the content piece to the userterminal via the file management system if connection information of theuser terminal is associated with the identifier of the content piece inthe contract, and the user terminal includes a storage device thatstores the file management control data, and a file management controlunit that acquires connection information of the right holder terminalfrom the contract that corresponds to the network identifier of the filemanagement system that manages the content piece, and requests thecontent piece from the right holder terminal via the file managementsystem.

A tenth feature of the present invention relates to an administratorprogram for causing a computer to function as the administrator terminalaccording to the first feature of the present invention.

An eleventh feature of the present invention relates to a participantprogram for causing a computer to function as the participant terminalaccording to the second feature of the present invention.

A twelfth feature of the present invention relates to a right holderprogram for causing a computer to function as the right holder terminalaccording to the third or fifth feature of the present invention.

A thirteenth feature of the present invention relates to a user programfor causing a computer to function as the user terminal according to thefourth or sixth feature of the present invention.

A fourteenth feature of the present invention relates to a datastructure of state data used for in a content use system that includes aplurality of file management systems and a distributed ledger systemincluding a distributed ledger that holds information on right holdersof content pieces managed by the file management systems. The datastructure of state data according to the fourteenth feature of thepresent invention is a data structure of state data that corresponds toa contract that corresponds to the file management systems, and thatassociates network identifiers that identify the file managementsystems, identifiers of content pieces managed by the file managementsystems that correspond to the network identifiers, and connectioninformation of a right holder terminal used by a right holder of acontent piece in the file management system, and the right holderterminal issues a right holder registration transaction for registeringan identifier of the content piece in the file management system inwhich the content piece is to be registered and connection informationof the right holder terminal in the file management system, in acontract that corresponds to the network identifier of the filemanagement system.

Effects of the Invention

According to the present invention, it is possible to provide anadministrator terminal, a participant terminal, a right holder terminal,a user terminal, a content use system, an administrator program, aparticipant program, a right holder program, a user program, and a datastructure of state data that enable information of a plurality of filemanagement systems to be managed by a single contract in a distributedledger.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a system configuration of a content usesystem according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a hardware configuration and functionblocks of an administrator terminal according to an embodiment of thepresent invention.

FIG. 3 is a diagram illustrating a data structure of state dataaccording to an embodiment of the present invention, and an example ofdata.

FIG. 4 is a diagram illustrating a data structure of state dataaccording to a variation, and an example of data.

FIG. 5 is a diagram illustrating a data structure of file managementcontrol data according to an embodiment of the present invention, and anexample of data.

FIG. 6 is a diagram illustrating a hardware configuration and functionblocks of a right holder terminal according to an embodiment of thepresent invention.

FIG. 7 is a diagram illustrating a hardware configuration and functionblocks of a user terminal according to an embodiment of the presentinvention.

FIG. 8 is a sequence diagram illustrating processing for generating afile management system in an embodiment of the present invention.

FIG. 9 is a sequence diagram illustrating right holder registrationprocessing in an embodiment of the present invention.

FIG. 10 is a sequence diagram illustrating user registration processingin an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Next, an embodiment of the present invention will be described withreference to the drawings. In the descriptions of the drawings below,the identical or similar parts are denoted with identical or similarreference numerals.

(Content Use System)

The following describes a content use system 100 in which anadministrator terminal 1, a right holder terminal 2, and a user terminal3 according to an embodiment of the present invention are used. Thecontent use system 100 includes a blockchain system (a distributedledger system) 6, a first file management system 9 a, and a second filemanagement system 9 b.

The first file management system 9 a and the second file managementsystem 9 b may be simply referred to as the file management system 9when they do not need to be particularly distinguish in this embodimentof the present invention. Although the content use system 100 shown inFIG. 1 includes two file management systems 9, the number may be anynumber as long as the number is two or more.

In the blockchain system 6, blockchain data (distributed ledger) B isshared between terminals that belong to the system. The blockchain dataB is data formed by connected blocks that include transactions issued byterminals that belong to the system. The blockchain system 6 includesthe administrator terminal 1, the right holder terminal 2, and the userterminal 3, and may include a plurality of blockchain control terminals4. Each of the terminals that belongs to the blockchain system 6establishes a P2P (Peer to Peer) connection via a blockchain network 5.As shown in FIGS. 2, 6 and 7, each of the terminals that belongs to theblockchain system 6 includes the blockchain data B and a blockchaincontrol unit for synchronizing the blockchain data B and processingtransactions.

In the blockchain data B, control information of content data fordistribution in the file management system 9 is registered for eachcontract that corresponds to the file management system 9. In theexample shown in FIG. 1, the blockchain data B includes controlinformation for the first file management system 9 a and controlinformation for the second file management system 9 b. The controlinformation includes identifiers of right holders and users of contentdata in the file management system 9, connection information, and thelike.

Transactions issued by the blockchain system 6 are verified by terminalsthat belong to the blockchain system 6 to form the blockchain data B. Ifthe execution of processing is specified in a transaction, theprocessing is executed by a terminal that belongs to the blockchainsystem 6, and the blockchain data B is updated.

The file management system 9 is managed by an administrator. The filemanagement system 9 includes the administrator terminal 1, the rightholder terminal 2, and the user terminal 3, and may include a pluralityof file system control terminals 7. In this embodiment of the presentinvention, the file management system 9 is a decentralized distributedfile management system in which the management of files is distributedamong the individual terminals that belong to the file management system9 such as an IPFS. Each of the terminals that belongs to the filemanagement system 9 establishes a P2P connection via a file managementnetwork 8.

In this embodiment of the present invention, the first file managementsystem 9 a and the second file management system 9 b are used indifferent operating processes and are controlled in secret from eachother.

The administrator terminal 1 is used by an administrator who manages thefile management system 9. The administrator terminal 1 connects to theblockchain system 6, the first file management system 9 a, and thesecond file management system 9 b. One administrator terminal 1 isdefined for one file management system 9, and an administrator who usesone administrator terminal 1 may manage multiple file management systems9.

The right holder terminal 2 is used by the right holder of a piece ofcontent managed by the file management system 9. The right holderterminal 2 connects to the blockchain system 6, the first filemanagement system 9 a, and the second file management system 9 b.Multiple right holders may be set for one piece of content, and rightholders may be set depending on the content of rights.

The user terminal 3 is used by a user of a piece of content managed bythe file management system 9. The user terminal 3 connects to theblockchain system 6, the first file management system 9 a, and thesecond file management system 9 b. Multiple users may be set for onepiece of content, and users may be set depending on the content ofrights.

In this embodiment of the present invention, the file management system9 is generated by the administrator terminal 1, and the right holderterminal 2 and the user terminal 3 function as participant terminals 10used by participants who participate in the generated file managementsystem 9, but there is no limitation to this. For example, theadministrator terminal 1 may function as the right holder terminal 2 orthe user terminal 3 in the content sharing process.

In the example shown in FIG. 1, the number of the blockchain controlterminals 4 and the file system control terminals 7 may be any number.The blockchain control terminal 4 and the file system control terminal 7may be different terminals, or alternatively may be a single terminalwith the function of the blockchain control terminal 4 and the functionof the file system control terminal 7.

Note that although the case where information on the right holder andthe user of a piece of content is registered in the blockchain data Bwill be described in this embodiment of the present invention, thepresent invention is not limited to this. For example, information onthe right holder and the user of a piece of content may be registeredusing another distributed ledger instead of the blockchain.

(Administrator Terminal)

The following describes the administrator terminal 1 according to anembodiment of the present invention with reference to FIG. 2. Theadministrator terminal 1 includes a storage device 110, a processingdevice 120, and a communication control device 130. The administratorterminal 1 may be a computer that includes the storage device 110, theprocessing device 120, and the communication control device 130, oralternatively may be a virtual computer constituted by multiple piecesof hardware. The functions shown in FIG. 2 are realized by such acomputer executing a conversion logic generation program.

The storage device 110 is a ROM (Read Only Memory), a RAM (Random AccessMemory), a hard disk or the like, and stores various pieces of data suchas input data, output data, and intermediate data for the execution ofprocessing by the processing device 120. The processing device 120 is aCPU (Central Processing Unit) that executes processing in theadministrator terminal 1 by reading and writing data stored in thestorage device 110, and inputting and outputting data to and from thecommunication control device 130. The communication control device 130is an interface for the administrator terminal 1 to communicably connectto the right holder terminal 2 and the user terminal 3.

The storage device 110 stores an administrator program, and also storesthe blockchain data B, file management control data C, first routingdata 111 a, and second routing data 111 b.

The blockchain data B is blockchain data synchronized among theterminals in the blockchain system 6 shown in FIG. 1. The blockchaindata B is updated by the blockchain control unit 121.

In an embodiment of the present invention, the blockchain data Bgenerates the file management system 9 and performs right processing forcontent managed by the file management system 9 in accordance withEthereum. The blockchain data B includes blockchain body data Bb andstate data Bs. The blockchain body data Bb is formed by connectingblocks in a chain. Each block contains multiple transactions, and ineach transaction, a contract may be set, or the execution of a contractmay be designated. In the state data Bs, a data area is provided foreach contract, and the contract data areas are updated as contracts areexecuted.

In an embodiment of the present invention, the state data Bs includes acontract that corresponds to the file management system 9. The contractis set with a program that executes processing in the file managementsystem 9 and a data area that is referenced to or updated when theprogram is executed. The state data Bs has a data structure in which anetwork identifier that identifies the file management system 9, anidentifier of a piece of content managed by the file management system 9that corresponds to the network identifier, and connection informationin the file management system 9 of the right holder terminal 2 used bythe right holder of the content are associated with one another. In anembodiment of the present invention, the state data Bs includes a dataarea that corresponds to the contract of the first file managementsystem 9 a and a data area that corresponds to the contract of thesecond file management system 9 b. The data areas for the first filemanagement system 9 a and the second file management system 9 b areindependent each other.

In an embodiment of the present invention, the state data Bs includesdata such as that shown in FIG. 3. The state data Bs includes data Bs1having items such as participants (Members) and a management file(ManageFile) for each network ID (NWID). Identifiers (IDs) of theparticipants on the blockchain system 6 and connection information(PeerlDs) on the file management system 9 corresponding to the networkID are stored in association with each other as participant information.The management file holds a file ID (fileCID) managed by the filemanagement system 9, a right holder ID (OwnerlD), right holderconnection information (OwnerPeerlD), user connection information(PermissionedPeerlD) and the like in association with one another. Here,the right holder ID is the ID of a right holder in the blockchain system6. The right holder connection information and the user connectioninformation are pieces of information for connecting to restrictiveterminals of the right holder and the user in the file management system9.

Various pieces of information shown in FIG. 3 may be encrypted by usinga common key that is held in common by the administrator terminal 1 andthe participant terminal 10 in the file management system 9. Byinformation in each file management system 9 in the state data Bs beingencrypted by using a common key for each file management system 9, thedata of each file management system 9 can be kept secret from a thirdparty such as a participant in another file management system 9.

Although FIG. 3 illustrates an example of a case where the state data Bshas, for each file management system 9, a contract for storinginformation on the participants and the management file of the filemanagement system 9, the present invention is not limited to this. Asanother example, as shown in FIG. 4, the state data Bs includes acontract Bs1′ that stores information on participants in the filemanagement system 9, and a contract Bs11′ and a contract Bs12′ thatrespectively store information on the files for each file managed by thecontract Bs1′. In the example shown in FIG. 4, more fine control can beperformed by providing access restrictions and restricting the range ofinformation leakage for each file, for example. The data structure ofthe state data Bs shown in FIGS. 3 and 4 is one example, and there is nolimitation to this example.

The state data Bs may be in any data format as long as a data area isallocated for each file management system 9, and it is possible toassociate information on content managed by a file management system 9by the network ID that identifies the file management system 9.

The file management control data C is data in which a network identifierthat identifies the file management system 9 is associated with anidentifier of a contract that is held by the blockchain system 6 andcorresponds to the network identifier.

In an embodiment of the present invention, while the administratorterminal 1 can access multiple file management systems 9, the contractsof individual file management systems 9 are independent from each otherin the blockchain data B. In view of this, the file management controldata C holds the file management systems 9 to which the administratorterminal 1 can connect and the identifiers of the contracts thatcorrespond to the file management systems 9 in association, andaccordingly the administrator terminal 1 can connect to multiple filemanagement systems 9 based on the appropriate contracts.

As shown in FIG. 5, the file management control data C may also holdvarious pieces of data such as a common key, connection information, andother participant connection information in addition to a network IDthat identifies a file management system 9, and a contract ID on theblockchain that corresponds to the file management system 9. The commonkey is used in the file management system 9 and is used to encrypt theconnection information and the like of an administrator or aparticipant. The common key is always held in the administrator terminal1.

The same connection information may be used as connection informationcorresponding each network ID. In this case, the connection informationmay be encrypted and shared with other participant terminals 10 by usinga hash value or the like of the common key that corresponds to eachnetwork ID as a private key.

The first routing data 111 a and the second routing data 111 b arepieces of information for specifying holders of files in the first filemanagement system 9 a and the second file management system 9 brespectively. The first routing data 111 a and the second routing data111 b may be simply referred to as routing data 111 if they are notparticular distinguished.

The routing data 111 is data in which the identifiers of files in thefile management system 9 are associated with the identifiers ofterminals that have the files. Each terminal that belongs to the filemanagement system 9 has the routing data 111. The identifiers of filesmanaged in the file management system 9 and the identifiers of terminalsthat have chunks of the content data are distributed and held by eachterminal. By integrating the routing data 111 of each terminal, it ispossible to specify the identifiers of all of the chunks of the contentdata managed in the file management system 9 and the identifiers of theterminals that have the chunks.

The processing device 120 includes a blockchain control unit 121, a filemanagement system generation unit 122, a first file management controlunit 123 a, and a second file management control unit 123 b.

The blockchain control unit 121 gently synchronizes the blockchain dataB with the blockchain data possessed by other terminals, thuscontrolling the blockchain data B to be in the latest state nearly inreal time. If multiple transactions are issued, the blockchain data B isupdated after verifying whether a block that includes the transactionsmay be added to the current blockchain body data Bb. Also, when a blockis to be added to the blockchain body data Bb, the blockchain controlunit 121 executes a contract program and refers to and updates the statedata Bs.

The file management system generation unit 122 issues a contractgeneration transaction for registering information regarding the filemanagement system 9 that is to be generated in the blockchain system 6.The contract generation transaction is processed by the blockchaincontrol terminal 4 or the like that belongs to the blockchain system 6,and the information regarding the file management system 9 that is to begenerated is registered in the state data Bs.

The contract generation transaction generates, in the blockchain data B,a contract which is corresponding to a network identifier thatidentifies the file management system 9 and associates with anidentifier of the participant terminal 10 in the blockchain system 6.The contract generation transaction then notifies the participantterminal 10 of the network identifier and the contract identifier.

Here, the file management system generation unit 122 may issue a commonkey in the file management system 9 that is to be generated. The commonkey is used to encrypt various pieces of information that are to beregistered in the contract.

The file management system generation unit 122 generates the filemanagement control data C after a contract of the file management system9 that is to be generated is generated in the blockchain system 6. Here,the file management control data C associates a network ID thatidentifies the file management system 9 with a contract ID, a commonkey, and the like.

Thereafter, the contract associates an identifier of the participantterminal 10 in the blockchain system 6 with connection information inthe file management system 9 for the participant terminal 10, in thestate data Bs. The contract also registers, in the state data Bs, anidentifier of a right holder of content, which is managed in theblockchain system 6, in the file management system 9 and connectioninformation in the file management system 9, as well as connectioninformation of a user of the content in the file management system 9.

Also, by the contract, identifiers of participants in the blockchainsystem 6 are associated in the state data Bs. As a result, theblockchain system 6 can reject a request for reference or update of thecontract from a third party that is not a participant.

The first file management control unit 123 a establishes a P2Pconnection with a terminal that belongs to the first file managementsystem 9 a, and the second file management control unit 123 bestablishes a P2P connection with a terminal that belongs to the firstfile management system 9 a. The first file management control unit 123 aand the second file management control unit 123 b may be simplydescribed as the file management control unit 123 when they are notparticularly distinguish.

When information of a file management system 9 that is to be generatedis registered in the blockchain data B by the file management system 9,the file management control unit 123 is formed as an instance thatcorresponds to the generated file management system 9. An instance ofthe file management control unit 123 is generated for each networkidentifier.

The file management control unit 123 issues a registration transactionfor registering connection information in the file management system 9for the administrator terminal 1 in a contract in the blockchain system6. Accordingly, the participant terminal 10 of the file managementsystem 9 can establish a P2P connection with the administrator terminal1. Also, the connection information of the administrator terminal 1registered here may be encrypted with a predetermined common key.

Also, the file management control unit 123 acquires connectioninformation in the file management system 9 for the participant terminal10 from the contract, and establishes a P2P connection with theparticipant terminal 10 based on the acquired connection information.The file management control unit 123 registers content in the filemanagement system 9 and manages the routing data 111 held by theadministrator terminal 1 via the P2P connection.

(Right Holder Terminal)

The following describes the right holder terminal 2 according to anembodiment of the present invention with reference to FIG. 6. The rightholder terminal 2 includes a storage device 210, a processing device220, and a communication control device 230. The storage device 210, theprocessing device 220, and the communication control device 230 aresimilar to the storage device 110, the processing device 120, and thecommunication control device 130 of the administrator terminal 1described with reference to FIG. 2.

The storage device 210 stores a right holder program and a participantprogram, and also stores the blockchain data B, the file managementcontrol data C, the first routing data 211 a, the second routing data211 b, and content management data 212.

The blockchain data B is similar to the blockchain data B of theadministrator terminal 1 described with reference to FIG. 2.

The file management control data C is similar to the file managementcontrol data C of the administrator terminal 1 described with referenceto FIG. 2. Note that although the common key is always held in theadministrator terminal 1, the right holder terminal 2 is not required toalways hold the common key, and the common key may be acquired from theadministrator terminal 1 as necessary.

The first routing data 211 a and the second routing data 211 b are alsosimilar to the first routing data 111 a and the second routing data 111b of the administrator terminal 1, but different data may be held insome cases.

The content management data 212 is data for managing the content dataregistered in the file management system 9. The content management data212 associates an identifier of a piece of content, a network ID of afile management system 9 in which the content is registered, andidentifiers of chunks that constitute the content. The contentmanagement data 212 may hold a table in which a content ID is associatedwith chunk IDs so that the content can be immediately identified inresponse to a chunk acquisition request.

The processing device 220 includes a blockchain control unit 221, afirst file management control unit 222 a, a second file managementcontrol unit 222 b, a registration unit 223, and a user registrationunit 224.

The blockchain control unit 221 is similar to the blockchain controlunit 121 of the administrator terminal 1 described with reference toFIG. 2.

The first file management control unit 222 a establishes a P2Pconnection with a terminal that belongs to the first file managementsystem 9 a, and the second file management control unit 222 bestablishes a P2P connection with a terminal that belongs to the secondfile management system 9 b. The first file management control unit 222 aand the second file management control unit 222 b may be simplydescribed as the file management control unit 222 when they are notparticularly distinguish.

After the file management system 9 is generated, the file managementcontrol unit 222 is notified by the blockchain system 6 of theidentifier of the contract that corresponds to the network identifierthat identifies the file management system 9. The file managementcontrol unit 222 issues a registration transaction for registeringconnection information in the file management system 9 for the rightholder terminal 2 (participant terminal 10) in the contract thatcorresponds to the notified contract identifier. At this time, theconnection information may be encrypted with the common keycorresponding to the file management system 9 that was notified from theblockchain system 6.

The file management control unit 222 further acquires connectioninformation of the administrator terminal 1 from the contract thatcorresponds to the notified contract identifier, and establishes a P2Pconnection with the administrator terminal 1 based on the acquiredconnection information. The file management control unit 222 similarlyestablishes a P2P connection with another participant terminal 10.

The file management control unit 222 registers content in the filemanagement system 9 and manages routing data 211 held by the rightholder terminal 2 via the P2P connection.

The file management control unit 222 further registers the fact that theright holder terminal 2 has the content in the contract of theblockchain system 6, and then gives a notification that the right holderterminal 2 has the content via the file management system 9 in which thecontent is managed. After receiving a content acquisition request from auser terminal 3 via the file management system 9 in which the content ismanaged, the file management control unit 222 transmits the content tothe user terminal 3 via the file management system 9. At this time, ifthe connection information of the user terminal 3 is associated with thecontent identifier in the contract that corresponds to the filemanagement system 9, the file management control unit 222 transmits thecontent to the user terminal 3 via the file management system 9.

The registration unit 223 issues a right holder registration transactionfor registering the right holder of content in the contract thatcorresponds to the file management system 9 in which the content is tobe registered. The right holder registration transaction is forregistering, in a contract that corresponds to the network identifier ofthe file management system 9, a content identifier in the filemanagement system 9 in which the content is to be registered, andconnection information in the file management system 9 for a rightholder terminal 2. Here, the connection information in the filemanagement system 9 for the right holder terminal 2 may be encryptedwith the common key of the file management system 9. According, the factthat new content was registered in the file management system 9, and theright holder of the content, can be notified to other terminals via theblockchain system 6.

Here, in the right holder registration transaction, the registrationunit 223 may further register, in the contract, an identifier of theright holder in the blockchain system in association with the contentidentifier. As a result, when the right holder terminal 2 issues atransaction for registering a user of the content, the user can beregistered by confirming that the transaction is from a legitimate rightholder of the content in the contract.

The user registration unit 224 issues a user registration transactionfor registering a user of the content in the contract. The userregistration unit 224 registers the user of the content after the rightholder of the content has been registered by the registration unit 223.The user registration transaction associates connection information inthe file management system for the user terminal 3 that is to use thecontent with the content identifier in the contract that corresponds tothe network identifier of the file management system 9 that manages thecontent. Here, the connection information in the file management system9 for the user terminal 3 may be encrypted with the common key of thefile management system 9. According, the fact that a user was set forcontent in the file management system 9, and information on the contentuser can be notified to other terminals via the blockchain system 6.

(User Terminal)

The following describes the user terminal 3 according to an embodimentof the present invention with reference to FIG. 7. The user terminal 3includes a storage device 310, a processing device 320, and acommunication control device 330. The storage device 310, the processingdevice 320, and the communication control device 330 are similar to thestorage device 110, the processing device 120, and the communicationcontrol device 130 of the administrator terminal 1 described withreference to FIG. 2.

The storage device 310 stores a user program and a participant program,and also stores the blockchain data B, the file management control dataC, the first routing data 211 a, and the second routing data 211 b.

The blockchain data B is similar to the blockchain data B of theadministrator terminal 1 described with reference to FIG. 2.

The file management control data C is similar to the file managementcontrol data C of the administrator terminal 1 described with referenceto FIG. 2. Note that although the common key is always held in theadministrator terminal 1, the user terminal 3 is not required to alwayshold the common key, and the common key may be acquired from theadministrator terminal 1 as necessary.

The first routing data 311 a and the second routing data 311 b are alsosimilar to the first routing data 111 a and the second routing data 111b of the administrator terminal 1, but different data may be held.

If the user terminal 3 holds data as a user of content, it may hold datasimilar to that of the content management data 212 of the right holderterminal 2 described with reference to FIG. 6.

The processing device 320 includes a blockchain control unit 321, afirst file management control unit 322 a, and a second file managementcontrol unit 322 b.

The blockchain control unit 321 is similar to the blockchain controlunit 121 of the administrator terminal 1 described with reference toFIG. 2.

The first file management control unit 322 a establishes a P2Pconnection with a terminal that belongs to the first file managementsystem 9 a, and the second file management control unit 322 bestablishes a P2P connection with a terminal that belongs to the secondfile management system 9 b. The first file management control unit 322 aand the second file management control unit 322 b may be simplydescribed as the file management control unit 322 when they are notparticularly distinguish.

After the file management system 9 is generated, the file managementcontrol unit 322 is notified by the blockchain system 6 of theidentifier of the contract that corresponds to the network identifierthat identifies the file management system 9. The file managementcontrol unit 322 issues a registration transaction for registeringconnection information in the file management system 9 for the userterminal 3 (participant terminal 10) in the contract that corresponds tothe notified contract identifier. At this time, the connectioninformation may be encrypted with the common key corresponding to thefile management system 9 that is notified from the blockchain system 6.

The file management control unit 322 further acquires connectioninformation of the administrator terminal 1 from the contract thatcorresponds to the notified contract identifier, and establishes a P2Pconnection with the administrator terminal 1 based on the acquiredconnection information. The file management control unit 322 similarlyestablishes a P2P connection with another participant terminal 10.

The file management control unit 322 registers content in the filemanagement system 9 and manages routing data 211 held by the userterminal 3 via the P2P connection. For example, after the filemanagement control unit 322 is notified that the right holder terminal 2has content via the file management system 9, the file managementcontrol unit 322 holds routing data to be held by the user terminal 3regarding the content.

Further, when the user terminal 3 is to use content, the file managementcontrol unit 322 acquires connection information of the right holderterminal 2 from the contract that corresponds to the network identifierof the file management system 9 that manages the content, and requeststhe content from the right holder terminal 2 via the file managementsystem 9.

The file management control unit 322 notifies the right holder terminal2 that the user terminal 3 desires to use the content via the blockchainsystem 6. At this time, if payment of a price is a condition, a sharingunit 324 pays the price according to the condition. If sharing of thecontent with the user terminal 3 is permitted, the right holder terminal2 issues a user setting transaction for registering the connectioninformation of the user terminal 3 in the identifier of the content thatis to be used in the contract of the blockchain system 6. At this time,the connection information of the user terminal 3 is registered in thecontract that corresponds to the network ID of the file managementsystem 9 in which the content to be used is managed.

(File Management System Generation)

The following describes processing for generating the first filemanagement system 9 a with reference to FIG. 8.

In step S101, when the first file management system 9 a is to begenerated, the administrator terminal 1 generates a common key thatcorresponds to the first file management system 9 a and a network IDthat identifies the first file management system 9 a. The administratorterminal 1 also generates administrator connection information in thefirst file management system 9 a.

In step S102, the administrator terminal 1 transmits, to the blockchainsystem 6, a contract generation transaction for generating a contractregarding the first file management system 9 a that is to be generated.The contract generation transaction includes the network ID of the firstfile management system 9 a and the ID of a participant that is toparticipate in the first file management system 9 a on the blockchainsystem 6.

In step S103, the administrator terminal 1 starts monitoring eventsrelated to the contract that was generated in step S102.

In step S104, based on a participant ID included in the contractgeneration transaction, the blockchain system 6 notifies a participantterminal 10 that participant registration was performed. Thisnotification includes the network ID of the first file management system9 a in which participant registration was performed and a contract IDthat includes information regarding the first file management system 9a.

In step S105, the participant terminal 10 generates a public key inorder to acquire the common key held by the administrator terminal 1,and starts monitoring events related to the contract that was generatedin step S102.

In step S106, the participant terminal 10 registers the public keygenerated in step S105 in the blockchain data B of the blockchain system6. In step S107, the participant terminal 10 generates connectioninformation for the participant in the first file management system 9 a.In step S108, the administrator terminal 1 acquires the public key thatwas registered in step S106.

In step S109, the administrator terminal 1 registers, in the blockchaindata B, the common key that was encrypted with the public key acquiredin step S108 and the administrator connection information in the firstfile management system 9 a that was generated in step S101. Theadministrator connection information is encrypted with the common key.

In step S110, the participant terminal 10 acquires the encrypted commonkey from the blockchain data B and the administrator connectioninformation that was encrypted with the common key. In step S111, theparticipant terminal 10 encrypts the participant connection informationthat was generated in step S107 with the common key and registers theencrypted participant connection information in the blockchain data B.

In step S112, the participant terminal 10 acquires other participantconnection information from the blockchain data B. In step S113, theadministrator terminal 1 acquires other participant connectioninformation from the blockchain data B. In step S114, the participantterminal 10 and the administrator terminal 1 establish a P2P connectionbased on connection destination connection information. A P2P connectionis also established with other participants.

In step S115, the participant terminal 10 manages the network ID, theconnection information of participants in the first file managementsystem 9 a and the like in the file management control data C.Similarly, in step S116, the administrator terminal 1 manages thenetwork ID, the connection information of participants in the first filemanagement system 9 a and the like in the file management control dataC.

(Right Holder Registration)

The following describes processing for registering content in the firstfile management system 9 a and registering a right holder of suchcontent in the blockchain data B with reference to FIG. 9.

In step S201, the right holder terminal 2 generates a content ID in thefirst file management system 9 a for content that is to be registered inthe first file management system 9 a. In step S202, the right holderterminal 2 issues a right holder registration transaction forregistering the content ID generated in step S201, a right holder ID inthe blockchain system 6, and right holder connection information in thefirst file management system 9 a. In step S203, various pieces ofinformation on the right holder is registered in a contract thatcorresponds to the first file management system 9 a based on the rightholder registration transaction.

In step S204, the right holder terminal 2 notifies the first filemanagement system 9 a that content is held, along with a content ID. Instep S205, the user terminal 3 is also notified that the right holderterminal 2 holds the content, along with the content ID. In step S206,the user terminal 3 stores routing information that is to be held by theuser terminal 3.

(User Registration)

The following describes processing for registering a user of contentthat was registered in the first file management system 9 a in theblockchain data B, and sharing the content with the user terminal 3 withreference to FIG. 10.

In step S301, the right holder terminal 2 issues a user settingtransaction for setting a content user in the blockchain data B. Theright holder terminal 2 refers to the file management control data C,specifies the contract ID that corresponds to the network ID of thefirst file management system 9 a, and transmits a user settingtransaction to the specified contract ID. The user setting transactionincludes the content ID, the ID of the right holder in the blockchainsystem 6, and user connection information that has been encrypted with acommon key.

In step S302, the blockchain system 6 determines whether the usersetting transaction that was transmitted in step S301 was issued by alegitimate right holder.

Specifically, the blockchain system 6 determines whether the ID of theright holder of the content ID in the contract that corresponds to thenetwork ID of the first file management system 9 a matches the rightholder ID that was received in step S301. If the IDs match, it isdetermined that the transaction was issued by a legitimate right holder,and in step S303, the blockchain system 6 registers the user connectioninformation that was transmitted in step S301 in the contract thatcorresponds to the first file management system 9 a.

In step S304, the user terminal 3 is notified that user registration wasperformed. This notification includes the network ID of the first filemanagement system 9 a that manages the content for which userregistration was performed, and the content ID.

In step S305, the user terminal 3 refers to the file management controldata C and specifies the contract ID that corresponds to the network IDof the first file management system 9 a that was received in step S304.The user terminal 3 then designates a content ID for the contract thathas the specified contract ID in the blockchain system 6, and makes aninquiry regarding connection information of the content right holder inthe first file management system 9 a. In step S306, the user terminal 3acquires right holder connection information that was encrypted with thecommon key. If the user terminal 3 does not hold the common key, theuser terminal 3 may issue a public key and acquire the common key thathas been encrypted with the public key as described with reference toFIG. 8.

In step S307, the user terminal 3 transmits a content acquisitionrequest via the first file management system 9 a based on the rightholder connection information that was acquired in step S306. The chunkIDs that make up the content are specified in this request. In stepS308, the content acquisition request that was transmitted from the userterminal 3 is transmitted to the right holder terminal 2.

In step S309, the right holder terminal 2 specifies the content ID fromthe chunk IDs that are designated in the content acquisition request. Instep S310, the right holder terminal 2 makes a user inquiry to thecontract that corresponds to the first file management system 9 a. Thisinquiry includes the requested content ID.

If the user is confirmed in step S311, the right holder terminal 2transmits the content via the first file management system 9 a in stepS312. In step S313, the user terminal 3 receives the content.

As described above, in accordance with the content use system 100according to an embodiment of the present invention, in the blockchainsystem 6, a different contract is generated for each file managementsystem 9, and information on content managed by the file managementsystems 9 is held in a data area that corresponds to each contract inthe state data Bs. As a result, the blockchain system 6 can manageinformation for multiple file management systems 9. Further, by holdingparticipant information for each file management system 9, the contentuse system 100 can perform control such that contract information is notleaked to anyone other than the participants. As a result, the contentuse system 100 can establish a file management system 9 for eachoperating process and ensure the confidentiality between operatingprocesses.

OTHER EMBODIMENTS

Although an embodiment of the invention has been described, thedescriptions and drawing ss that form part of this disclosure does notintend to limit the present invention. Various alternative embodiments,examples, and operational techniques will be apparent to those skilledin the art from this disclosure.

For example, each terminal such as the administrator terminal describedin an embodiment of the present invention may be configured in one pieceof hardware as shown in FIG. 2, or alternatively may be configured inmultiple pieces of hardware depending on the functionality and thenumber of processing.

It goes without saying that the present invention includes variousembodiments not described herein.

Accordingly, the technical scope of the present invention is definedonly by the matter specifying the invention according to the claims, asreasonable from the above description.

REFERENCE SIGNS LIST

-   1 Administrator terminal-   2 Right holder terminal-   3 User terminal-   4 Blockchain control terminal-   5 Blockchain network-   6 Blockchain system-   7 File system control terminal-   8 File management network-   9 File management system-   10 Participant terminal-   100 Content use system-   110, 210, 310 Storage device-   111 Routing data-   120, 220, 320 Processing device-   121 Blockchain control unit-   122 File management system generation unit-   123, 222, 322 File management control unit-   130, 230, 330 Communication control device-   212 Content management data-   223 Registration unit-   224 User registration unit-   B Blockchain data-   Bb Blockchain body data-   Bs State data-   C File management control data

1.-6. (canceled)
 7. A content use system that includes a file managementsystem managed by an administrator, a distributed ledger systemincluding a distributed ledger, an administrator terminal used by theadministrator, and a participant terminal used by a participant whoparticipates in the file management system, the administrator terminalcomprising: a file management system generation unit configured to issuea contract generation transaction for generating, in the distributedledger, a contract in which a network identifier that identifies thefile management system is associated with an identifier of theparticipant terminal in the distributed ledger system, and notifying theparticipant terminal of the network identifier and an identifier of thecontract; and a file management control unit configured to issue aregistration transaction for registering, in the contract, connectioninformation of the administrator terminal in the file management system,acquire connection information of the participant terminal in the filemanagement system from the contract, and establish a P2P connection withthe participant terminal based on the acquired connection information,and the participant terminal comprises: a file management control unitconfigured to, in response to being notified by the distributed ledgersystem of the identifier of the contract that corresponds to the networkidentifier that identifies the file management system, issue aregistration transaction for registering, in the contract thatcorresponds to the notified contract identifier, connection informationof the participant terminal in the file management system, acquireconnection information of the administrator terminal from the contractthat corresponds to the notified contract identifier, and establish aP2P connection with the administrator terminal based on the acquiredconnection information.
 8. A content use system that includes a filemanagement system, a distributed ledger system including a distributedledger, a right holder terminal used by a right holder of a contentpiece, and a user terminal used by a user of the content piece, whereinthe right holder terminal comprises: a storage device configured tostore file management control data in which a network identifier thatidentifies the file management system is associated with an identifierof a contract that is held in the distributed ledger system andcorresponds to the network identifier; a registration unit configured toissue a right holder registration transaction for registering thenetwork identifier of the file management system in which a contentpiece is to be registered, an identifier of the content piece in thefile management system, and connection information of the right holderterminal in the file management system, in the contract that correspondsto the network identifier; and a file management control unit configuredto give a notification that the right holder terminal has the contentpiece via the file management system, and the user terminal comprises: astorage device configured to store the file management control data; anda file management control unit configured to hold routing data that isto be held by the user terminal in response to being notified that theright holder terminal has the content piece via the file managementsystem.
 9. A content use system that includes a file management system,a distributed ledger system including a distributed ledger, a rightholder terminal used by a right holder of a content piece, and a userterminal used by a user of the content piece, wherein the right holderterminal comprises: a storage device configured to store file managementcontrol data in which a network identifier that identifies the filemanagement system is associated with an identifier of a contract that isheld in the distributed ledger system and corresponds to the networkidentifier; a user registration unit configured to issue a user settingtransaction for associating, in the contract that corresponds to thenetwork identifier of the file management system that manages thecontent piece, an identifier of the content piece with connectioninformation of the user terminal that is to use the content piece in thefile management system; and a file management control unit configuredto, in response to receiving an acquisition request for acquisition ofthe content piece from the user terminal via the file management system,transmit the content piece to the user terminal via the file managementsystem if connection information of the user terminal is associated withthe identifier of the content piece in the contract, and the userterminal comprises: a storage device configured to store the filemanagement control data; and a file management control unit configuredto acquire connection information of the right holder terminal from thecontract that corresponds to the network identifier of the filemanagement system that manages the content piece, and request thecontent piece from the right holder terminal via the file managementsystem. 10.-14. (canceled)